Well-drilling apparatus



own. 18, 1930...

' w. SHELDON 1,781,707

WELL DRILLING APPARATUS Filed may 16, 1927 2 Sheets-Sheet l NOV. 18, 1930. w, s N 1,781,707

WELL DRILLING APfARATU-S Filed May 16, 192! 2 Sheets-Sheet 2 IN V EN TOR.

Patented Nov. 18, 1930 OFFICE WALDO SHELDON, OF SOUTH NORWALK CONRE C TICUT WELL-DRILLING APPARATUS Application filed May 16,

This invention relates particularly to rotary drills such as used in bringing in deep oil wells.

The objects of the invention are to provide 6 practical and eflicient means for automatically controlling the feed of the drill so as to keep substantially the same weight on the bit irrespective of the varying formations which the bit encounters and thus keep the drill Operating substantially uniformly without the constant attention of the driller; to accomplish the desired results with relatively simple, inexpensive mechanism, and, in the case Where the invention is combined with the power feed drills disclosed in prior patents of mine, to utilize the power of the automaticfully disclosed.

The drawings accompanying and forming part of this specification illustrate two simple embodiments of the invention but this illustration is primarily for purposes of disclosure so it is to be understood that the invention is of broader scope than this particular illustration, as will be apparent from the breadth and scope of the followingdescription and claims.

.. The first view in the drawing is a broken.

part sectional and more or less diagrammatic representation of an embodiment of the 1nvention as combined with a pressure feed drill of the type disclosed in my Patent 1,674,069. Figure 2 is a part sectional view of the invention as combined with the hydraulic feed cylinder of an ordinary rotary. The drill shown in' Figure 1 will be seen to consist of a rotary table 1 journaled 111 a suitable base structure 2 and having sl-i'dlngly keyed withinits bore, a drive sleeve?) carrying at the top a grip or chuck 4 WlllCll can be set to firmly and positively hold the drill pipe 5. Long-stroke power cylinders 6 supported in the base at opposite sides of the table contain pistons 7 having projecting PIS- ton rods 8 connected with the ends of a beam 1927. Serial No. 191,795.

or head 9 extending across the table and havmg a collar portion 10 engaged between upper and lower annular thrust shoulders 11, 12 on the drive sleeve. 5 By controlling admlssion of water or other fluid under pressure to the cylinders above or below the pistons, the drive sleeve will be lowered or raised 'to feed or to lift the drill, without interfering with the rotation.

In deep drilling, the weight of the string is ordinarily more than sufiicient for properly feeding the bit so the feed isusually accomplished by partially sustaining the string and taking away the sustaining force as the bit progresses. The rate of progression depends upon ,the formation, the action slowing up with a sticky or hard formation and accelerating with a lightero'r softer formation.

In. the machine illustrated, the feeding has been accomplished heretofore by the provision of a bleed which would relieve the pressure under the piston or pistons at a predetermined rate. This did not take account of irregularities in the formation and the driller was. therefore obliged to continually watch the operation and adjust the feed as conditions seemed to warrant or require. This at best is uncertain and results are entirely dependent upon the vigilance and skill of the driller; The present invention relieves the driller of such responsibility and provides forthe automatic advancement of the bit directly and immediately in accordance with the formation encountered. This automatic control is effected by utilizing the variations in pressureoccurring in the feed cylinder or cylinders coincident with the variations in formation.

The variations in feed cylinder pressure will be observed to be as follows: When loose or soft formation is encountered, the bit will feed faster and thus have a tendency to drop, adding the weight of the drill string to the pistons-and hence increasing the pressure below the pistons. Under these conditions the drill may be allowed to feed faster and hence the invention contemplates the provision of means operative under these circumstances to relieve this excess pressure in the cylinders and permit the bit to feed down at a proportionately faster rate.

When hard or stick formation is encountered, the bit is in e ect sustained by the formation and hence a-portion of the weight of the drill string is taken off the power pistons and the pressure is accordingly reduced in the cylinders. Under these circumstances,

pressure is automatically admitted beneath the pistons to restore the proper balance and reduce the feed of the bit to a rate suited to that particular formation.

In the construction illustrated, the automatic compensation in the feed is effected by means of a pump or liquid pressure supplying device operative to supply the necessary sustaining power to the pistons and controlled as to its action by high and low pressure control devices subjected to the cylinder pressure.

The pressure supply means is indicated at 14 as a constantly running pump taking liquid from a tank 15 through a suction line 16 and passing the liquid under pressure through a pressure supply conduit 17 to the lower ends of the cylinders beneath the pistons therein. This pump is capable of supplying the liquid at a pressure somewhat in excess of that required, which, for example, may be in the neighborhood of three hundred pounds per square inch. If the pressure in the cylinders exceeds the predetermined amount which in the example may be considered as three hundred pounds, the excess of pressure is automatically by-passed,

in the illustration, by means of a by-pass valve 18, opening to conduit 17 and adapted when lifted from its seat 19 to open a way through a by-pass relief 20.

To subject this relief Valve to the cylinder pressure,ra branch 21 is shown extending from conduit 17 to a chamber 22 containing a diaphragm 23 acting on a stem 24 positioned to lift the valve from its seat. This stem and diaphragm are acted on by a spring 25 which is placed under the proper tension to allow seating of the valve up to the pre- 7 determined maximum pressure by an adjusting nut 26 screwed on the stem as an abutmerit for the spring.

A gage is indicated at 27 in the branch line leading to the diaphragm to facilitate the proper setting of the valve closing spring. An upwardly opening check valve 28 in the supply conduit holds the desired pressure in the cylinders when the excess pressure from the pump is being by-passed through the relief line 20.

The excess flow from the pump which is thus automatically by-passed away from the power cylinders may be returned to the tank or other source of liquid supply, or in the case of ample water supply, may be simply wasted. In the present disclosure, however,

- the excess flow and the energy which it represents is saved and utilized as a source of quick power for raising the drive sleeve after it has reached the end of its feed stroke. The by-pass relief 20 is therefore shown extended as a conduit 20 to a pressure storage tank 29. This tank is indicated as of closed construction so that the air trapped therein will build up a pressure on the liquid sufiicient for the purpose of raising the pistons in the power cylinders and their attached load. A pressure of one hundred pounds is ordinarily more than ample for this purpose and it may be considered for purposes of illustration that tank 29 is constructed to hold the liquid at this pressure, which it will be noted is below the maximum .pump pressure used in the control of the feed.

The capacity of the pump is such that under normal or average conditions, the flow by-passed fromthe pump will be suflicient .to maintain a reserve of pressure in tank 29 for returning the drive sleeve after each downward feeding operation.

Whenthe maximum reserve pressure is attained in tank 29, the excess is by-passed from said tank, for instance, by means of the valve indicated at 30 and adapted to be lifted from its seat by the stem 31 governed by diaphragm 32, which valve when so operated opens flow through a by-pass return 33 to tank 15. The controlling diaphragm 32 is shown subjected to the tank pressure by a branch 34 taken olf from the reserve tank' be provided in the by-pass connection 20, as

indicated at 38, to avoid any effect of the reserve tank pressure on the bypass line for the pump.

The automatic control thus far described will be seen to be effective to pass the pressure flow from the pump to the pressure cylinders whenever and so long as the pressure in said cylinders is below the predetermined maximum for which the diaphragm valve is set and. to by-pass the pressure flow from the pump away from the power cylinders just as soon as the pressure therein has reached the desired maximum value. The practical result of this is that whenever the bit strikes hard formationfor is otherwise retarded in its progress and thus takes more of the weight of the drill string off the power cylinders, a proportionate reduction in pressure occurs in said cylinders, beneath the supporting pistons, and this'reduced pressure enables the by-pass check to close, thus placing the pressure side of the pump in direct communication with the power cylinders. Consequently, as soon as the progress of the drill is retarded, the apparatus immediately becomes effective to lift the bit or a portion of the weight on the bit and thus free it to such an extent as to enable it to continue its proper operation.

The bleed line by which the rate of feed is governed is indicated at 39 and is shown controlled by a hand valve 40. This valve is set so as to allow the sustaining fluid to escape from beneath the pistonsat such a rate as to give the desired drill feed for a particular formation, or understood conditions and may be varied 'to increase or reduce the feed as may be required or may seem desirable. f

If soft or loose .formation is encountered, the tendency of the bit is to drop away. When this occurs the bit can with safety be fed at a faster rate and this is accordingly automatically accomplished by that part of the control apparatus shown at the right and consisting of a valve 41, controlling a cylinder pressure reducing by-pass 42 and adapted to be lifted from its seat by a stem 43 governed by a diaphragm 44 which is subjected to cylinder pressure by a branch 45. This cylinder pressure relief is shown connected in with the supply conduit 17, since that carries'cylinder pressure. The so-called drop ping of the bit in light or free formation adds a proportionately increased amount of weight on the supporting pistons, raising the pressure in the cylinders to that extent and this increase in pressure is utilized as the means for automatically opening valve 41. With the opening of valve 41, the cylinder pressure by-passes through relief conduit 42 until such pressure is brought back to the normal or predetermined amount, whereupon valve 41 automatically closes and the power cylinders again feed the dull at the normal or usual rate.

Byutilizing the variations in pressure in the feed cylinders, a most sensitlve and prompt feed control is attained because t will be seen that this cylinder pressure s immediately responsive to any var1at1ons 1n opposition to the feed of the drill. The controls are relatively simple and can be readily set to maintain anydesired sustaining pressure in the feed cylinders.

The two main controls, that is, the pump by-pass control valve 18 and the cylinder by:v -pass control valve 41, may be set w1th1n a few pounds of each other so that the pump will supply pressure to the feed cylinders until the pressure in the cylinders reaches a predetermined maximum, say three hundred poundsfthe pump then becoming ineffective to'in'crease thatpressure and the second device then taking control to rel eve the cylinder pressure if'it builds up beyond a predetermined maximum of say three hundred and inders. preferably situated in position convenient tothe driller so that he need not move from his ten pounds. By the combination of these controls and the bleed valve it will be evident that practically any desired feed of the drill can be accomplished.

When the pump is not supplying pressure to the cylinders, it is utilized, as much as may be necessary, to supply pressure to the'reserve tank 29, which is thus automatically kept supplied with a suflicient body of liquid to quickly return the power pistons back to the beginning of their stroke. Thus, no time is lost in pumping the pistons back to their upper position. When the end of the down stroke is reached, and the grip holding the drill pipe is released, it is. only necessary for the driller to open valve 36, the liquid under pressure in tank 29 being thereby admitted to the cylinders to quickly return the pistons to the starting position of the feed stroke. After a fresh grip is taken on the pipe, the valve 36 may be closed and the automatic feeding proceeded with as before to conserve the water or other liquid employed. The .bleed may be discharged into the return line by a branch connection 46 to the return pipe 42.

The hand valve 36 is shown as a three-way valve interposed in the connections from the two main controls and the reserve tank to the cylinders, said valve being thus adapted in pressure, and in the reverse position, to out off both controls at 17 and open up the reserve pressure line into the cylinder pressure line 17. It will be noted that the bleed line 39 is connected into the cylinder pressure line 17 below the three-way valve so that in the act of cutting off the two automatic controls the bleed line will also be shut off. Thus a single three-way valve can be utilized to switch over from feed control operation to the quick return operation and that-for all these several operations, only one pipe line is necessary from the control devices to the power cylinders; namely, that part of the line 17 extendmg from the three-way valve over to the cyl- These various control devices are normal station to adjust and operate the same.

In Figure 2 the adaptability of the invention to the hydraulic feed cylinder of an ordi nary rotary drill is shown, the same reference characters being used where possible to designate parts corresponding to those already described. In this view an ordinary rotary table is indicated at47 with a hydraulic swivel at 48 suspended by the piston 49 in a hydraulic cylinder 50 supported from the crown block. The feed is controlled in this instance by regulating the escape of water from the lower end of the cylinder through the cylinder pressure line 17. By adjusting the bleed 40, the normal rate of feed can beset at the desired rate. The

two main control valves 18 and 41 operate to automatically maintain the feed in accordance with the predetermined cylinder pressure and the three-Way valve 36 enables the piston to be quickly brought back to the top of its stroke at the end of each automatic drill feeding action.

As pipe lengths are added to the drill stem, the controls may be adjusted from time to time to compensate for such extra weight. If the drill string is not long enough to provide the necessary drilling pressure, positive drilling pressure may be applied for admitting fluid under pressure into the upper ends of the feed cylinders and the automatic controls may then be utilized to keep this positive feeding force constant for different formations encountered. Valve means may be provided for changing over from positive feed to lifting force and the change-over from down pressure to upward pressure may be effected either manually or automatically, according as conditions require.

What is claimed is: V

1. I11 well drilling apparatus, hydraulic cylinder mechanism for governing the feedlng of a drill string, pressure supply and exhaust connections with the cylinder of said mechanism, control devices for said connections subjected to said cylinder pressure and operative thereby to supply fluid under pressure to the cylinder or to release pressure therefrom to maintain Within limits a substantially constant cylinder pressure and means operative independently of said automatic operation for supplying fluid under pressure to the cylinder for effecting a return stroke movement of the hydraulic cylinder mechanism.

2. In Well drilling apparatus, a hydraulic drill feed cylinder, a pump for supplying the pressure fluid thereto, a control device subjectedto the cylinder pressure and actuated thereby to automatically by-pass the pump flow away from the pressure cylinder when the pressure in .said cylinder exceeds a predetermined maximum and a second control device subjected to the cylinder pressure and actuated thereby to release the pressure fluid from the cylinder when the pressure exceeds a predetermined maximum.

3. In well drilling apparatus, a hydraulic cylinder, a piston therein operative in one stroke to govern the drill feed, a pressure storing reserve tank for containing a reserve sup ly of fluid for effecting rapid return stro e of the piston, a pump for supplying actuating fluid to the cylinder and reserve tank, connections from the pump to the cylinder and reserve tank and means automatically governed by the pressure in the cylinder and reserve tank for controlling the flow from the pump to the cylinder and reserve tank.

HOW away from both the cylinder and reserve tank.

5. In Well drilling apparatus, a hydraulic cylinder, a piston therein operative in one stroke to govern the drill feed, a pressure storing reserve tank for containing a reserve supply of fluid for effecting rapid return stroke of the piston, a pump for supplying actuating fluid to the cylinder and reserve tank, connections from the pump to the cylinder and reserve tank and means automatically governed by the pressure in the cylinder and reserve tank for controlling the flow from the pump to the cylinder and reserve tank, said means including mechanism forautomatically by-passing the pressure fluid away from the cylinder to the reserve tank.

6. In well drilling apparatus, a hydraulic cylinder, a piston therein operative in one stroke to govern the drill feed, a tank for containing a reserve supply of fluid for effecting rapid return stroke of the piston, a pump for supplying actuating fluid to the cylinder and reserve tank, connections from the pump to the cylinder and reserve tank, means automatically governed by the pressure in the cylinder and reserve tank for controlling the floW from the pump to the cylinder and reserve tank, said means including mechanism for automatically by-passing the pressure fluid away from the cylinder to the reserve tank and mechanism for automatically by-passing said by-pass flow away from the reserve tank.

7. In apparatus of the character disclosed, a feed cylinder and a piston therein, a regulatable relief for venting the pressure fluid from said cylinder, a pump for supplying pressure fluid to the cylinder and means subjected to the cylinder pressure and actuated thereby'to automatically by-pass the flow from the pump independently ofthe action of said regulatable relief away from the cylinder when the cylinder pressure reaches a predetermined limit, a second relief from the cylinder and means subjected to cylinder pressure and actuated thereby to automatically control said second relief.

8. In apparatus of the character disclosed, a pressure. cylinder and connections therefrom for governing the feed of a drill string,

pressure operated control devices subjected to the cylinder pressure and actuated thereby to govern the feeding action of the pressure cylinder, a main pressure supply for connection with the cylinder during the drill feed operation, a reserve pressure supply for furnishing the energy for quick return movement in the pressure cylinder and valve mechanism for switching over from one source of pressure supply to the other.

19. In apparatus of the character disclosed, a pressure cylinder and connections therefrom for governing the feed of a drill string, pressure operated control devices subjected to the cylinder pressure and actuated thereby to govern the feeding action of the ressure cylinder, a main'pressure supply or connection with the cylinder during the drill feed operation, a reserve pressure supply for furnishing the energy for the return move- -ment in the pressure cylinder, valve mechanism for switching over from one source of pressure supply to the other and a bleed line adjustable to fix a predetermined normal rate of feed, said bleed line being arranged to be cut out of service simultaneously with the automatic controls when the valve mechanism is operated to cut 011' the main pressure supply and cut in the return feed supply.

In well drilling apparatus, the combination of a rotary table, a drill string rotated thereby, a hydraulic cylinder and connections therefrom by which feed of the drill string rotated by the table is governed, valve means connected with the hydraulic cylinder, pressure actuated means responsive to cylinder pressure and actuated thereby to operate said valve means in accordance with varying cylinder pressures to increase or decrease the feed of the drill effected by the hydraulic cylinder, a reserve pressure storing tank, means for automatically bypassing motive fluid in excess of that required for the hydraulic cylinder to said reserve pressure storing tank and valve means for enabling utilization of the stored reserve pressure when required.

11. In well drilling apparatus, the combination of a rotary table, a drill string rotated thereby, a hydraulic cylinder and connections therefrom by which feed of the drill string rotated by the table is governed, valve meansconnected with the hydraulic cylinder, pressure actuated means responsive to cylinder pressure and actuated thereby to operate said valve means in accordance with yarying cylinder pressures to increase or decrease'the feed ofthe drill effected by the hydraulic cylinder, a reserve pressure storing tank, means for automatically by-passing motive fluid in excess of that required for the hydraulic cylinder to said reserve pressure storing tank, valve means for enabling utilization of the stored reserve pressure when required and valve means connected with the hydraulic feed cylinder for a predetermined normal feed operation, the valve means for enabling utilization of the stored reserve pressure being connected to render said normal feed valve mechanism inoperative.

12. Inwell drilling apparatus, the combination of a rotary table, a drill string rotated ,thereby, hydraulic feed mechanism supporting the drill string and by which feed of the drill string rotated by the table is governed, valve means controlling the operation of said hydraulic feed mechanism and a diaphra m acted on by the varying pressure in sa' d hydraulic feed mechanism and actuated thereby to regulate the valve means to thereby directly govern the drill feed in accordance with existing pressure in the hydraulic feed mechanism.

13. In well drilling apparatus, the combination of a rotary table, a drill string rotated thereby, hydraulic feed mechanism supporting said drill string and by which the feed of said drill string-is governed, valve means controlling operation of said hydraulic feed mechanism, a pressure actuated device acted on by the varying pressure in said hydraulic feed mechanism and operated thereb to regulate said valve means and there y governing the drill feed in accordance with existing pressure in the hydraulic feed mechanism and a variably adjustable device for releasing pressure from the hydraulic feed mechanism independently of the control exercise by the pressure actuated means, said pressure actuated means having connection with the hydraulic feed mechanism separate from said variably adjustable pressure release means, whereby adjustment of said independent pressure release means will not affeci: operation of said automatic feed contro 14;. In well drilling apparatus, the combination of a rotary table, a drill string rotated thereby, hydraulic feed mechanism supporting the drill string and by which the feed of said drill string is governed, variably adjustable means for releasing pressure from said hydraulic feed mechanism at a desired rate, valve means for; releasing pressure from the hydraulic feed mechanism at a faster rate than permitted by the variably adjustable pressure release means aforesaid.

and independently of the latter and a pressure actuated device acted on by pressure of.

the hydraulic feed mechanism and actuated by increased pressure in said hydraulic feed mechanism to operate said valve, means to automatically efi'ect advance of the drill feed faster than permitted by the variably adjustable pressure release means aforesaid.

In testimony whereof I hereunto afiix my signature.

- 'WALDO SHELDON. 

